Estimation method for Heterogeneous Retardation Effects in Geological Disposal of Radioactive Waste

放射性废物地质处置中异质延迟效应的估算方法

基本信息

批准号：
11680509
负责人：
NIIBORI Yuicih
金额：
$ 2.24万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680509/
关键词：
Radioactive Waste Geological Disposal Retardation Effect Spatial Distribution Tracer Response Sorption Mathematical Model Physical Model 二次元数学モデル

项目摘要

The relation between the mass transport rate and the spatial distribution of retardation coefficient, R_d, has been examined.To express the distribution of retardation effects, this study used the two-dimensional packed bed with two kinds of silica, i.e., silica sand and silica gel particles. The solution of Eu(III) as a tracer was injected into the packed bed. Based on the experiment results of the breakthrough curve, this study proposed two-dimensional mathematical model to explain the retardation effects with two-dimensional advection-dispersion.Using the calculated breakthrough curves, next, we focused on the peak height and its arrival time. To compare them easily, the dimensionless mean residence time was always set at unity. In the results, when the R_d values were distributed perpendicular to the flow direction, the peak height and its arrival time strongly depended on the R_d distribution. This study, for simplicity, considered two kinds of R_d layers, assuming that the small R_d and the large were arranged parallel to one another. The smaller the alternation frequency of the layers became, the higher peak and the shorter arrival-time the breakthrough curve showed. In contrast, as the frequency was large enough, the peak-arrival time almost agreed with the homogeneous case.Further, this study confirmed that the variation of the skewness of R_d had no appreciable influence on the whole mass transport rate. When the 2-D distribution of R_d was described by, e.g., log-normal distribution, the average mass transport rates showed agreement with those on the other probability density functions defined by the same set of the arithmetic mean and the standard deviation of R_d. These tendencies mentioned above were confirmed in the range of Peclet number from 10 to 10^2 for the dimensionless standard deviation at least up to around 1.

已经检查了质量传输速率与延迟系数的空间分布之间的关系R_D。为了表达延迟效应的分布，本研究使用了带有两种硅胶的二维包装床，即硅胶砂和硅胶颗粒。将欧盟（III）作为示踪剂的溶液被注入包装床中。基于突破性曲线的实验结果，这项研究提出了二维数学模型来解释使用二维对流分散的延迟效应。使用计算出的突破性曲线，接下来，我们专注于峰高及其到达时间。为了轻松比较它们，始终将无量纲的平均停留时间设定为团结。在结果中，当垂直于流动方向分布R_D值时，峰高和其到达时间强烈取决于R_D分布。为简单起见，这项研究考虑了两种R_D层，假设小的R_D和大型层是平行的。层的交替频率越小，突破性曲线显示的峰值较高，到达时间较短。相比之下，由于频率足够大，峰值到达时间几乎与均匀的情况一致。法术，这项研究证实，R_D偏度的变化对整个质量传输率没有明显的影响。当R_D的2-D分布由例如对数正态分布的分布描述时，平均质量传输速率显示与其他概率密度函数相同的算术均值和R_D的标准偏差所定义的其他概率密度函数一致。上面提到的这些趋势在第10到10^2的范围内被确认，对于无量纲的标准偏差，至少在1左右。